A dental prosthesis such as a crown is one means for artificially reproducing functions of a lost natural tooth. An exterior of a natural tooth is formed hard by enamel and has a unique texture. A natural tooth affects not only the function of mastication but also impression of a human's face. Thus, preferably, a dental prosthesis having as close color and texture to a natural tooth as possible is used. As one method for improving so-called aesthetics of a dental prosthesis as described, for example, Patent Literature 1 proposes a dental prosthesis that consists of a plurality of layers having an inside layer of low transparency and an outside layer of high transparency as disclosed. According to this, the inside layer shields the color of an abutment from the exterior view, and the aesthetic property can be improved by the outer layer of high transparency and the inside layer seen through the outer layer.
Patent Literature 1 discloses that the inner layer is cast first and then, the outer layer is cast on the inner layer as a method for manufacturing such a dental prosthesis having a plurality of layers.